Eurovision Song Contest organisers have warned that they may ban countries from the contest if broadcasters disclose information about voters' identities.

The BBC reported that the warning came after a number of people in Azerbaijan were questioned by police because they had voted for a song by neighbouring Armenia in this year's contest. The two states fought over the disputed Nagorno-Karabakh region in the 1990s.

The European Broadcasting Union (EBU) said the rule change would ensure the protection of voters' privacy.

Last month, an Azerbaijani man told the BBC that he had been accused of being unpatriotic and a "potential security threat", after he sent a text backing Armenia's song, Jan Jan.

The country's authorities said people had merely been invited to explain why they voted for Armenia.

The EBU's director general, Jean Reveillon, said violating the privacy of voters "or interrogation of individuals... is totally unacceptable".

As it does not have the ability to penalise telephone companies, the EBU said it would impose sanctions against national broadcasters "for any disclosure of information which could be used to identify voters".

Banning a national broadcaster would effectively stop a country from being able to take part in the contest.